1. Field of the Invention
The present invention relates to an adjustable lumbar support apparatus for a seat back, and more particularly to a lumbar support structure installed in the seat back of a chair.
2. Description of Related Art
For better comfort of sitting, the functions of the chair become more and more diverse. For example, by installing wheels on the chair, the chair is conveniently movable. By adjusting the height of the chair, the chair is suitable for people with different sizes or for different usage circumstances. By adjusting the slope angle of the seat back, a user's back can be supported appropriately. Accordingly, a consumer can choose to purchase the suitable chair in accordance with personal preference.
In order to support the waist when a person is sitting on the chair, the manufacturer installs a lumbar support on the seat back of the chair. Since the lumbar support is protruded from the seat back, the waist of the person can be supported to relieve the sore waist condition. Moreover, in order to have a proper elasticity of the lumbar support so as to acquire a better supporting effect, most of the lumbar supports are fixed at two sides and include a hollow part at a middle to provide a suitable cushioning support for the waist.
However, the required waist supporting strength is different for different people and a distance of the lumbar support protruding from the seat back is fixed, so the lumbar support is not suitable for different people with different requirements or one person's requirements under different circumstances. In addition, when a person has been sitting on the chair for a period of time, the lumbar support will be gradually elastic fatigued and the supporting effect of the lumbar support will be decreased.
Accordingly, the conventional lumbar support is fixed on the seat back and the distance between the lumbar support and the seat back cannot be varied. The problems that the conventional lumbar support is not suitable for different people and the distance between the lumbar support and the seat back cannot be adjusted need to be resolved.